The class of polymers of carbon monoxide and olefin(s) has been known for some time. Brubaker, U.S. Pat. No. 2,495,286, produced such polymers of relatively low carbon monoxide content in the presence of free radical initiators, e.g., peroxy compounds. U.K. No. 1,081,304 produced similar polymers of higher carbon monoxide content in the presence of trialkylphosphine complexes of palladium compounds as catalyst. Nozaki extended the process to produce linear alternating polymers in the presence of triarylphosphine complexes of palladium moieties and certain inert solvents. See, for example, U.S. Pat. No. 3,694,412.
More recently, the class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon has become of greater interest in part because of the greater availability of the polymers. These polymers, now becoming known as polyketones or polyketone polymers, are produced according to more recent processes which are illustrated by a number of published European Patent Application Nos. including 121,965, 181,014, 213,671 and 257,663. The process typically involves contacting the monomeric reactants under polymerization conditions in the presence of an alkanolic reaction diluent and a catalyst composition formed from a compound of a Group VIII metal selected from palladium, cobalt or nickel, the anion of a strong non-hydrohalogenic acid and a bidentate ligand of phosphorus, arsenic or antimony. The resulting polymers are relatively high molecular weight materials having established utility in the production of shaped articles such as containers for food and drink by procedures which are conventional for the processing of thermoplastic polymers.
In the process of producing the polymers, the choice of catalyst composition precursors is of considerable importance in determining the activity of the catalyst composition which results but the choice of reaction diluent is also of significance. The polymerization process is suitably conducted in aprotic reaction as illustrated by copending U.S. patent application Ser. No. 271,130, filed Nov. 14, 1988, now U.S. Pat. No. 4,921,938, reaction rate is often rather low in aprotic diluents. The most frequent diluents of choice are protic diluents such as alkanols and particularly preferred is methanol, in part because of the more rapid reaction rate obtainable by the use of such diluents. The use of a methanol/water mixture as reaction diluent is shown by copending U.S. patent application Ser. No. 213,731 filed June 30, 1988, now U.S. Pat. No. 4,889,914 methanol reaction diluent did not substantially effect the polymerization rate. It would be of advantage to provide additional polymerization diluents which provide generally high rates of polymerization.